JPH0158746B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rotor winding abnormality diagnosing device for a rotating electric machine such as a large-capacity turbine generator, and more particularly to an abnormality diagnosing device suitable for detecting an interlayer short circuit in a rotor winding. .

Generally, a large-capacity turbine generator is comprised of a stator 1 and a rotor 3 disposed opposite to the stator 1 with a gap 2 in between, as shown in FIG. The stator 1 is constructed by winding a stator winding, that is, an armature winding 6, around a laminated stator core 4 having a ventilation duct 5, and the rotor 3 is integrally formed with a shaft portion 7. It is constructed by winding a rotor winding, that is, a field winding 9 consisting of 5 to 10 layers of conductors mutually insulated between layers, around the formed body, that is, the rotor core 8, The rotor winding 9 is held in the slot by a wedge 10 and its ends are covered by a retaining ring 11.

By the way, if the interlayer insulation of the rotor winding is destroyed due to the winding's thermal expansion or mechanical shock, and the winding is short-circuited, generally speaking, in a two-pole turbine generator, the N and S poles of the rotor will be damaged. Magnetic imbalance occurs, including magnetomotive force imbalance, and as a result, abnormal vibration occurs. When abnormal vibration occurs, there is a risk that the generator will be adversely affected, such as damage to the generator's bearings and breakdown of the insulation in the windings, and may eventually become inoperable. Therefore, it is necessary to promptly detect an interlayer short circuit in the rotor winding and take necessary measures.

A known method for detecting this interlayer short circuit in the rotor winding will be described below.

In FIG. 1, FIG. 2a schematically shows the flow of magnetic flux in a plane where the rotor is sliced into rings, that is, a plane in which a radial cross section is developed. The magnetic flux is roughly divided into two types; one is a main magnetic flux 12 shown by a solid line in the figure, and the other is a leakage magnetic flux 13 that surrounds the rotor winding and shown by a broken line. For the purpose of capturing this leakage magnetic flux 13, for example, a magnetic flux detection element 14 such as a stationary search coil is installed in the air gap. Then, leakage magnetic flux 13 generated when current flows through the rotating rotor winding 9 is caught.

Figure 2b shows the waveform of this leakage flux, and its magnitude is closely related to the product of the current flowing through the rotor winding conductors surrounding the leakage flux and the number of conductors, that is, the number of amperes. As the number of amperes decreases, the leakage flux decreases, and conversely, as the amperage increases, the leakage flux increases accordingly.

Therefore, when an interlayer short circuit occurs in the rotor winding, the number of amperes produced by the winding decreases, and the amount of leakage magnetic flux eventually decreases.

On the other hand, as shown in FIG. 2c, an induced voltage with a pulsating waveform corresponding to the leakage flux is generated in the search coil 14 for detecting the leakage flux. If the rotor winding is healthy, it will have a pulsating waveform as shown by a solid line 15, for example. However, if an interlayer short circuit occurs in a certain rotor winding, and the leakage magnetic flux at that part becomes small as shown by the broken line 16 in FIG. The peak value of the corresponding pulsating waveform becomes smaller. In general, in a rotating electrical machine such as a turbine generator, magnetic flux is equal in magnitude and opposite in sign on the north and south pole sides, and the leakage flux and the induced voltage of the search coil for detecting magnetic flux are also symmetrical. It has a sexual nature.

From the above, in the induced voltage waveform of the search coil, the peak value of each wave of the corresponding pulsating waveform on the N-pole side and the S-pole side, for example, the peak value in Figure 2 c.
Compare P ₁ and Q ₁ and check whether there is a difference in size,
If there is a significant difference, it can be determined that an interlayer short circuit has occurred in the rotor winding with the smaller peak value.

Therefore, conventionally, a person took a photograph of the signal waveform from the magnetic flux detection element and compared the corresponding points on the north and south pole sides one by one to check for interlayer short circuits, but this was time-consuming. It is time-consuming, inefficient, and difficult to deal with in emergencies.

Furthermore, in response to the demands of the times, there has recently been a desire to constantly monitor on-line the presence or absence of interlayer short circuits in the rotor windings of turbine generators, and automatic diagnostic devices such as those described below have been considered.

FIG. 3 is a schematic block diagram of the automatic diagnostic device. In the figure, 17 is a rotating electrical machine section consisting of a rotating electrical machine and a magnetic flux detection element attached to it.
The pulsating waveform signal detected by the magnetic flux detection element is sent to the determination device 19 through the signal line 18. The determination device 19 is roughly divided into a processing device 20 and a monitoring device 2.
The processing device 20 captures the peak value of each wave of the signal waveform and performs abnormality diagnosis processing to determine whether there is an abnormality in the turbine generator. If,
If it is determined that there is an abnormality in the turbine generator,
A signal indicating an abnormality is transmitted through a signal line 21 to a monitoring device 22, where the signal is processed.

FIG. 3 has a specific configuration as shown in FIG. 4, for example. In Fig. 4, magnetic flux detection element 1
4. For example, a search coil is installed near the surface of the rotor 3, and the magnetic flux detecting element 14 is used to detect magnetic flux generated near the surface due to the current flowing through the rotor winding, such as leakage magnetic flux. . A pulsating waveform signal generated in the magnetic flux detection element 14 by the electromagnetic induction effect of this leakage magnetic flux is transmitted to the processing device 20 in the determination device 19 through the signal line 18. The signal is first made into an appropriate size by the amplifier 23 and passed through the signal line 24 to the peak value holder 2.
5 and is transmitted to the comparator 26 through the signal line 27a. The peak value holder 25 is configured to hold the peak value for a time sufficient for the comparator 26 to input the peak value signal, and then automatically release the holding before the next pulsating peak value arrives. When the comparator 26 outputs an input start signal to the peak value holder 25 through the signal line 27b to indicate that input of the peak value may be started, the peak value signal is transmitted to the comparator 26 through the signal line 27a.

The comparator 26 sequentially inputs the peak values held by the peak value holder 25 for one cycle and stores the data in the recorder 28 through the signal line 29a, while the data is sequentially recorded through the signal line 29b. The peak value data of the symmetrical parts is inputted from the device 28, and the peak value data of the symmetrical parts are compared, and the difference between the two with respect to the larger peak value, that is, the relative difference, is, for example,
Checks whether a set level, such as 10%, has been exceeded. If the level exceeds the set level, it is determined that there is an abnormality, and a signal is transmitted to the monitoring device 22 through the signal lines 21a and 21b to inform the monitoring device 22 of the extent of the abnormality and the location where the abnormality has occurred.

The monitoring device 22 is composed of an alarm device 30 consisting of an alarm lamp, a buzzer, etc. that is activated by a signal transmitted through a signal line 21a, and a display panel 31 that displays the location and degree of abnormality using a signal transmitted through a signal line 21b. ing.

According to this automatic diagnostic device, it is possible to automatically determine the presence or absence of an interlayer short circuit in a rotor winding in a turbine generator or the like. However, automatic diagnostic devices in general, including this example, have the following drawbacks.

When the rotor of a turbine generator is cooled with gas or liquid, if these coolants do not uniformly cool the rotor, the heat distribution on the rotor surface will be uneven, and the rotor body will cool down well. Thermal expansion is small in areas where the rotor is cooled, and conversely, thermal expansion is large in areas that are poorly cooled, eventually causing the rotor to bend. In this case, rotor vibration occurs even if there is no interlayer short circuit in the rotor windings, and the distance between the rotor surface and the magnetic flux detection element changes as it rotates, so the vibration induced in the magnetic flux detection element changes. The pulsating waveform signal also fluctuates, and if a diagnosis is made based on this fluctuating waveform signal, there is a risk of making an incorrect diagnosis.

In addition, since the magnetic flux detection element is installed near the rotor surface, a signal line is installed to transmit the pulsating signal of the leakage magnetic flux to the processing device. Because there is a strong magnetic field nearby, there was a possibility that noise would be induced in the signal line. For example, as shown in Fig. 5, the peak value P ₂
Noise 32 appears at the peak value Q ₂ to be compared.
If it becomes larger, there is a risk that the winding in the slot corresponding to the smaller peak value Q ₂ will be determined to have an interlayer short circuit.

Further, as described above, the gas-cooled turbine generator includes a stator ventilation duct through which cooling gas passes in order to cool the stator core and rotor. When detecting leakage magnetic flux near the surface by inserting a rod-shaped probe with a magnetic flux detection element fixed to the tip into the inner diameter side of the ventilation duct into the air gap near the rotor surface, the probe is exposed to the cooling gas. As the distance between the magnetic flux detecting element and the rotor surface changes, the pulsating waveform signal induced in the magnetic flux detecting element fluctuates, creating a risk of misdiagnosis.

By the way, in general, when an interlayer short circuit occurs in the rotor winding, the effective amperage of the rotor decreases as described above, so the amount of magnetic flux generated by the rotor decreases, and this magnetic flux eventually induces it in the stator winding. The voltage also decreases. Typically, turbine generators are equipped with automatic voltage regulators that increase the rotor current as the stator winding terminal voltage decreases to maintain a constant voltage. Therefore, when an interlayer short circuit occurs, the rotor current increases. Therefore, the current current value is compared with the past (normal) rotor current value when the stator voltage, stator current, and power factor are the same, and it is determined whether the current current value has increased or not. A method of diagnosing the presence or absence may also be considered. However, with this method, it can be determined that an interlayer short circuit has occurred, but it is unclear in which slot winding of the rotor the short circuit occurred, and it is also unclear whether it occurred in one location or in multiple locations. do not know.

An object of the present invention is to provide a highly reliable rotor winding abnormality diagnostic device for a rotating electric machine that can accurately, reliably, and quickly determine the occurrence location and degree of interlayer short circuit in the rotor winding. be.

To achieve this objective, the present invention comprises a stator voltage detector, a stator current detector and a power factor detector for detecting the voltage, current and power factor of the stator windings;
A rotor current detector detects the current in the rotor winding, and a normal state corresponding to the value of each detection signal from the stator voltage detector, stator current detector, and power factor detector. means for determining the current value of the rotor winding in the rotor winding, and comparing the current value determined by this means with the current value detected by the rotor current detector to determine the current detected by the rotor current detector. and a second comparison/judgment means for outputting a second abnormality signal when the current value is larger than the current value determined by the means, and the second comparison/judgment means outputs a second abnormality signal. The present invention is characterized in that the first abnormality signal from the first comparison/judgment means is made valid.

Hereinafter, the present invention will be explained in detail based on illustrated embodiments.

FIG. 6 is a block diagram showing the overall configuration of a rotor winding abnormality diagnosing device according to an embodiment of the present invention.
In this figure, a magnetic flux detection element 14 is installed in the rotating electrical machine section 17, and leakage magnetic flux near the surface of the rotor 3 is detected. The magnetic flux pulsation signal detected by the magnetic flux detection element 14 is sent to the processing device 20 through the signal line 18, where it is determined whether there is an interlayer short circuit. When an interlayer short circuit occurs, the location and extent of the short circuit are calculated, and an alarm signal is sent to the switch 33 via the signal line 21a, and a signal indicating the location and extent of the abnormality is sent via the signal line 21b. The rotor current of the rotating electric machine is detected by a rotor current detector 35 installed in the rotor excitation lines 34a and 34b that send current from the stationary side to the rotor windings, and the current value is detected by a determiner via a signal line 36. Sent to 37. On the other hand, stator voltage,
The stator current and power factor are determined by a stator voltage detector 39 and a stator current detector 4 installed on power lines 38a to 38b, respectively, which transmit power induced in the stator windings.
0, the power factor is detected by the power factor detector 41, and the voltage value is sent to the determiner 37 via the signal line 42, the current value via the signal line 43, and the power factor via the signal line 44. The determiner 37 is composed of a recorder 45 and a comparison controller 46, and signals on signal lines 42, 43, 44, and 36 are input to the recorder 45. The recorder 45 is a comparison controller 46
When receiving the control signal sent from the controller via the signal line 47, the values of stator current, voltage, power factor, and rotor current are recorded. In this way, rotor current values corresponding to various conditions (stator voltage, current, power factor) when the rotating electric machine is normal are recorded on the recorder. By the way, if you have finished recording the normal values,
When the control signal from the comparison controller 46 enters the recorder via the signal line 48, the recorder 45 records the normal rotor current value corresponding to the current stator voltage, current, and power factor via the signal line 49. and sends it to the comparison controller 46. Comparison controller 46 compares this current value with the current rotor current value sent from rotor current detector 35 via signal line 50 to determine whether the value has increased. When it is increasing, an interlayer short circuit occurrence signal is transmitted from the comparison controller 46 to the switch 33 via the signal line 51. The switch 33 is
When the interlayer short circuit occurrence signal is received, the alarm signal, abnormality location, and degree signal sent via the signal lines 21a and 21b are sent to the monitoring device 22 via the signal line 52a.
or 52b. When the monitoring device 22 receives the signals from the signal lines 52a and 52b, it issues an alarm and displays the location and extent of the interlayer short circuit.

According to this embodiment of the present invention, it is possible to accurately and automatically determine whether there is an interlayer short circuit in a rotor winding in a turbine generator or the like. The rotor winding current value of a rotating electric machine such as a turbine generator is automatically stored in correspondence with the stator voltage, stator current, and power factor during normal times, and this recorded current value during normal times in the past is stored. The value is compared with the current rotor current value, and only when the value is increasing, the processing device processes the magnetic flux signal near the rotor surface and transmits the diagnosis result to the monitoring device, which issues an abnormality alarm or detects an abnormality. Display the location and degree of occurrence. Therefore, reliable diagnosis can be made without being affected by noise superimposed on the signal line that transmits signals from the magnetic flux detection element to the processing device or vibrations of the rotor caused by uneven cooling of the rotor.

FIG. 7 shows another embodiment of the present invention, which differs from FIG. 6 in the configuration of the determiner 37. The determiner 37 is composed of a memory 53 and a comparator 54, and the memory 53 records in advance rotor currents under normal conditions corresponding to various stator voltages, stator currents, and power factors. Then, the normal rotor current value corresponding to the current stator voltage, current, and power factor is output to the comparator 54 via the signal line 55, and the comparator 54 outputs this value and the rotor current detector. Detected at 35 and signal line 3
6 is compared with the current value transmitted via 6.
When the detected current value is larger than the normal value,
A positive signal is sent to the switch 33 via the signal line 51, and only when the signal on the signal line 51 is positive, the switch 33 transmits the alarm signal, abnormality location, and degree signal on the signal lines 21a and 21b. The information is transmitted to lines 52a and 52b.

When the determiner 37 is configured as described above, the circuit configuration becomes extremely simple and the cost of the device becomes low.

FIG. 8 shows that the determiner 37 is connected to the arithmetic unit 56 and
It consists of 4. The arithmetic unit 56 connects the signal line 42,
When the stator voltage, stator current, and power factor are input through 43 and 44, the rotor current value during normal operation is automatically calculated according to the pre-stored calculation procedure, and the calculated value is sent to the signal line. 57 to the comparator 54.
The comparator 54 compares this value with the current value detected by the rotor current detector 35 and transmitted via the signal line 36, and when the detected current value is larger than the normal value, it is determined as correct. The signal is sent to the switch 33 via the signal line 51.

Configuring the determiner 37 as described above provides the following effects. In general, recorders are used for various stator voltages,
It is large because it records the value of rotor current corresponding to stator current and power factor, but compared to that,
Since the arithmetic unit can be made smaller, the entire device can be made smaller and the price can also be reduced.

As explained above, according to the present invention, there are provided a stator voltage detector, a stator current detector, and a power factor detector that detect the voltage, current, and power factor of the stator winding, and the rotor winding current and power factor detector. A rotor current detector detects the rotor winding in a normal state corresponding to the value of each detection signal from the detection signals of the stator voltage detector, stator current detector, and power factor detector. means for determining a current value; and comparing the current value determined by this means with the current value detected by the rotor current detector, and the current value detected by the rotor current detector is determined by the means. and a second comparison/judgment means for outputting a second abnormal signal when the current value is larger than the current value, and when the second abnormality signal is output from the second comparison/judgment means, the first comparison/judgment is performed. Since the first abnormal signal from the means is made valid, the rotor winding is not affected by the noise superimposed on the lead wire that transmits the pulsating waveform signal from the magnetic flux detection element or by rotor vibration. The occurrence location and degree of interlayer short circuit can be detected accurately, reliably, and quickly, and as a result, the reliability of the rotating electric machine can be significantly improved.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view of the main parts showing the schematic configuration of a turbine generator. Figures 2 a to c are schematic diagrams showing the flow of magnetic flux on the rotor surface, a pulsating waveform diagram of leakage magnetic flux on the rotor surface, and a search coil. Figures 3 and 4 are schematic and detailed block diagrams of a conventional rotor winding abnormality diagnosis device, and Figure 5 shows the pulsating waveform of the induced voltage generated in the search coil. Pulsation waveform diagram when
8 through 8 are block diagrams of a rotor winding abnormality diagnosing device according to each embodiment of the present invention. 1...Stator, 2...Gap, 3...Rotor, 1
4... Magnetic flux detection element, 20... Processing device (first
determination device), 22... Monitoring device, 33... Switch, 35... Rotor current detector, 37... Judgment device, 39... Stator voltage detector, 40... Stator current detector, 41...Power factor detector, 45...Recorder, 46...Comparison controller (second determination device), 5
3...Storage unit, 54...Comparator (second determination device), 56...Arithmetic unit.

Claims (1)

[Scope of Claims] 1. A stator having a stator winding wound around a stator core, and a stator having a rotor winding wound around a rotor core, which is disposed facing the stator with a gap therebetween. a magnetic flux detection element that is arranged near the surface of the rotor and detects magnetic flux generated near the rotor surface by the current flowing through the rotor windings; In the pulsating waveform signal,
Sequentially input the peak value of each wave of the pulsating waveform component corresponding to the first magnetic pole of the rotor and the peak value of each wave of the pulsating waveform component corresponding to the second magnetic pole different from the first magnetic pole of the rotor. a peak value holding means for holding the peak value for a predetermined time;
The wave height value of each wave of the pulsating waveform component corresponding to the first magnetic pole is sequentially input from this wave height value holding means in a predetermined temporal relationship with the position signal synchronized with the rotation of the rotor obtained from the position detection device. a storage means for storing the pulse height value of each wave of the pulsating waveform component corresponding to the second magnetic pole newly held in the wave height value holding means, and sequentially inputting and storing the wave height value of each wave of the pulsating waveform component corresponding to the second magnetic pole in a predetermined temporal relationship with the position signal; and a first comparing and determining means that compares the wave height value of each wave of the pulsating waveform component corresponding to the first magnetic pole stored in the means and outputs a first abnormal signal when the difference is greater than or equal to a predetermined value. a stator voltage detector, a stator current detector and a power factor detector for detecting the voltage, current and power factor of the stator winding; and a rotor current detector for detecting the current of the rotor winding. a detector, and means for determining a current value of the rotor winding in a normal state corresponding to the value of each detection signal from each detection signal of the stator voltage detector, the stator current detector, and the power factor detector; , the current value determined by this means is compared with the current value detected by the rotor current detector, and the current value detected by the rotor current detector is determined to be higher than the current value determined by the means. A second signal that outputs a second abnormal signal when the signal is large.
and when the second abnormality signal is output from the second comparison and judgment means, the first
A rotor winding abnormality diagnosing device for a rotating electric machine, characterized in that the first abnormality signal from the comparison and determination means is validated. 2. In claim 1, the means for determining the rotor winding current value includes detection signals from the stator voltage detector, stator current detector, and power factor detector and the rotation In addition to recording the detection signal from the child current detector in correspondence,
Each of the detection signals input from the correspondence of each detection signal in the normal state recorded in advance by inputting the current detection signals of the stator voltage detector, stator current detector, and power factor detector. A rotor winding abnormality diagnosing device for a rotating electric machine, comprising a recorder that reads out a rotor winding current value during normal operation corresponding to the value of . 3. In claim 1, the means for determining the rotor winding current value inputs and stores in advance each detection signal of the stator voltage detector, stator current detector, and power factor detector. From the correspondence between the stator winding voltage, current, and power factor during normal operation and the rotor winding current, the rotor winding current value during normal operation corresponding to the value of each of the detection signals inputted is determined. A rotor winding abnormality diagnosing device for a rotating electric machine, comprising a memory device to be read. 4. In claim 1, the means for determining the early rotor winding current value inputs each detection signal of the stator voltage detector, stator current detector, and power factor detector and calculates each detection signal. A rotor winding abnormality diagnosing device for a rotating electrical machine, comprising a computing unit that calculates a rotor winding current value in a normal state corresponding to signal values.